Polymers have been widely investigated in the coatings industry for a number of applications, such as adhesives, sealants, clear coats, powder coats, and low adhesion backings. With appropriate choice of polymer backbone, polymers can be applied to a wide variety of surfaces. Although thermosetting compositions have been used as coatings and/or adhesives for a wide variety of these applications, many known thermosetting compositions lack desirable properties for at least some of these applications. For example, many thermosetting compositions require a solvent, which would make the use of such a composition undesirable for applications such as skin or tissue adhesives.
The use of topical skin adhesives for medical closures continues to grow. Compared to conventional closure techniques such as sutures and staples, topical skin adhesives offer potential benefits to medical professionals. Exemplary benefits of using topical skin adhesives include a potential reduction in the time required to close an incision or laceration, and less skin trauma, which can result in an improved cosmetic outcome.
Current skin adhesive products are typically cyanoacrylate-based adhesives. Cyanoacrylate-based skin adhesive products generally consist of liquid monomers, do not contain solvent, and require no mixing prior to application. Cyanoacrylate monomers can polymerize in the presence of nucleophiles (e.g., hydroxide ion), and the polymerization is not inhibited by oxygen. The rate of polymerization can vary based on a number of factors including, for example, the moisture content of the environment, and the characteristics of the skin (e.g., nucleophile content of the skin). The polymerization rate can generally be accelerated by exposure of cyanoacrylate-based adhesives to additional nucleophiles such as amines. Although cyanoacrylate-based adhesives can provide materials with high tensile strength and high shear strength, the lack of elasticity and flexibility has practically limited the use of cyanoacrylate-based adhesives to incisions that are not under high tension. The use of cyanoacrylate-based adhesives in surgical procedures has also been limited by variable cure time and high cost.
There is a continuing need for rapidly curing thermosetting adhesives, particularly adhesives that can be formulated with minimal or no solvent.